Field of the Invention
The present invention relates to a method of checking an abnormality in the oil pressure of a transmission control unit (TCU). More particularly, the present invention relates to a technology able to determine an abnormality in an oil pressure signal transmitted from a TCU to an electric oil pump (EOP) and inspect an EOP flow variation learning logic based on the determination, thereby ensuring that the EOP supplies oil in a reliable manner and preventing a transmission from being damaged.
Description of Related Art
An EOP flow variation learning logic of the related art will be described in brief in order to help the understanding of the present invention.
FIG. 1 is a flowchart illustrating an EOP flow variation learning logic of the related art. The EOP flow variation learning logic is realized in a TCU.
As illustrated in FIG. 1, the EOP flow variation learning logic generally includes step S10 of starting learning, step S20 of satisfying a learning environment, step S30 of learning the revolutions per minute (RPM) of an EOP by measuring an oil pressure, and step S40 of completing the learning.
At the step S10 of starting learning, the TCU transmits a preset oil pressure signal from to the EOP through controller area network (CAN) communication.
Afterwards, it is determined whether or not a learning environment for the TCU to learn variations in the oil flow supplied from the EOP is satisfied.
At the process of determining whether or not the learning environment is satisfied, requirements are, for example: 1) the temperature of automatic transmission fluid (ATF) ranging from 40 to 100° C.; 2) a gear position at P position or N position; 3) no absolute pressure sensor (APS) input; and 4) no malfunction of an oil pump unit (OPU), a TCU and other pressure sensors. When these requirements are satisfied, the TCU is determined to be prepared for the learning.
Afterwards, the step of learning the RPM of the EOP by measuring the oil pressure is carried out. According to the learning, an EOP RPM map stored in the TCU is corrected. The EOP RPM map consists of oil temperatures and oil pressures according to the EOP flow variation learning logic.
The present invention is intended to improve the above-described EOP flow variation learning logic. An object of the present invention is to provide a method of checking an abnormality in the oil pressure of a TCU able to allow the EOP to revolve at an optimum RPM by determining whether or not an oil pressure signal transmitted from the TCU to the EOP is normal, with the RPM of the EOP being optimized in consideration of the mileage of a vehicle.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.